Apparatus for grinding, smoothing, and polishing glass.



Patented Aug. .29, I899.

A. MARSH.

G. APPARATUS FOR GRINDING, S MOOTI'IING AND POLISHING GLASS.

(Applicatiomfiled Feb. 7, 1898.)

(No Model.)

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which the glass sheets are laid.

To all whom, it may concern:

away, of a portion of a glass-holding table UNITED STATES PATENT iOrrrctnz.

GEORGE A. MARSH, OF PITTSBURG, PENNSYLVANIA, ASSIGNOR TO THE MARSH PLATE GLASS COMPANY, OF SAME PLACE.

APPARATUS FOR GRINDING, SMOOTHING, AND POLISHING GLASS.

SPECIFICATION forming part of Letters Patent No. 631,898, dated August 29, 1899.

Application filed February '7 1898.

Be it known that I, GEORGE A. MARSH, of Pittsburg, in the county of Allegheny and State'of Pennsylvania, have invented a new and useful Improvement in Apparatus for Grinding, Smoothing, and Polishing Glass, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, forming part of this specification, in which Figure 1 is a top plan View, partially broken constructed in accordance with my invention. Fig. 2 is a cross-section on the line II II of Fig. 1. Fig. 3 is a View similar to Fig. 1, showing another form of table and the one which I prefer in actual practice. Fig. 4 is a crosssection on the line IV IV of Fig. 3, and Fig. 5 is a detail perspective View of a section of another form of the table.

My invention relates to that class of tables for holding glass during the operation of grinding, smoothing, or polishing it wherein a vacuum is employed for holding the glass sheets in place. In my prior patents, Nos. 477,303, 477,305, and 477,306, dated June 21, 1.892, and No. 488,925, dated December 27, 1892, covering apparatus of this character I have described a glass-holding table the upper face of which was provided with a multiplicity of cells either by means of a system of projecting ribs, a reticulated packing laid upon the table, or other suitable means. I have now discovered thatI can employ a table for this purpose having a substantial part of its face constituting aflat supporting-surface for the glass by exhausting the air from between the glass sheet and its flat supportingsurface and that I obtain important advantages by the use of this flat-faced table. I am enabled to use this fiat supporting-surface by employing means for exhausting air from between the glass sheet and the surface, also by surrounding at least a major part of a flat supporting-surface which is connected to a vacuum apparatus by a seal, and further by laying upon the flat supporting-surface connected to the vacuum a flat covering or packmg, which is preferably porous and upon My invention consists in the abovemen Serial No. 669,439. (No model.)

tioned separate combinations, and further in the construction and arrangement of the parts, as. more fully described, and set forth in the claims.

In the drawings, referring to the form of Figs. 1 and 2, 2 represents a portion of a table containing vacuum-chambers 3 and fluidchambers 4,arranged alternatelytherein. The upper face of this table constitutes a flat supporting-surface and is provided with a series of water-channels 5, sunken therein. The fluid-chambers 4 connect with these channels by holes 6, and the vacuum-chambers communicate with the upper face of the table through holes 7, these vacuum-chambers being connected to any desirable apparatus for exhausting air from them. I prefer to employ water in the fluid-chambers, but it will be understood that other fluids may be employed, as I intend to cover the construction independent of the particular fluid used. These fluidchambers may be connected to any suitable source of supply.

In using this table I cover its top with a flat layer of porous material, such as paper or closely-woven cloth, and lay the glass sheets upon this packing, they being placed so that their edges are between the holes leading to the vacuum-chambers. The vacuum apparatus'being started into operation, a suction is produced on the lower faces of the glass sheets, which holds them in place during the grinding or polishing; Preferably at about the same time that thevacuum apparatus is started I supply water under a light pressure to the fluid-chambers of the table, and this water, seeping up through the holes into the water-channels and constantly moistening the packing, seals the edges of the glass sheets around the flat supporting-surfaces on which they rest, so that a sufficient vacuum 'isv obtained to hold the sheets in place. The water also moistens the lower faces of the glass sheets and prevents their being stained and serves to regulate the temperature of the table, which without this fluid would rise to too high a point on account of the heat generated by the friction of the polishing-blocks upon the glass when the glass is being polished. Although it is ordinarily preferable to interpose between the under surface-of the glass sheet and the top of the table a sheet of porous material which would form vacuum-cells, such porous sheet is not necessary, as it is practically impossible to make the surfaces of the table and sheet of glass so true and flat that they would bear are supported on a ribbed surface. ble is also simpler .and cheaper to construct and operate. i

upon each other at all points, and hence it will be possible to cause the air to flow laterally under the sheet of glass to the ports or table.

are turned over and again held by reestablishing the vacuum.

in Figs. 3 and 4 I show a table the upper vface of which is provided with cells such as described in my prior patents, each cell having a series of supporting-ribs Bsym-metrically arranged therein. This table is provided with vacuum-chambers 9, arranged ,alternately with fluid-chambers 10, each cell communicating with a-vacuum-chamber by a hole or holes 11. The water-channels are connected with the fluid-chambers by holes 12, arranged at intervals. To convert this table, which is of the cell or rib-top class, into a table havinga flat supporting-sur-face for the sheets, I cover its top :with a thin perforatedsheet of metal 18, which maybe made in one or several partsand which is fastened. thereon, so as to seal the various air and water channels from each other. This sheet maybe made of copper, aluminium, or other desirable material which will not rust under the action of the water and will afford .a flat bearing-surface for the glass. The perforations in this metal sheet are so arranged as tocommunicate with the various air and water channels, and when the flat sheet-packing is placed upon it and the glasssheetslaid upon the packing, with their edges matched between the holes, the operation will be the same as before described with the form of Figs, 1 and 2. I

In the form of Fig. 5 I show a table which is the same as that of Figs. 1 and 2, except that in place of the water-channel I employ a series of holes 14, which connect the flat bearing-surface with the fluid-chamber. The operation of this table is the same as that of the other forms.

The advantages .of my invention will be apparent to those skilled in the art. A more uniform bearing-surface for the glass sheet is afforded than with the cell or rib-top table, and I have discovered that the fiatsupporti-ng-surface obviates a marking of the glass sheets, which sometimes results when they The ta- The table may be provided atany desirable points with grooved channels leadingfrom; the holes communicating with the vacuumchambers or with additional water-channels. The shape and arrangement of the chambers and the holes may be otherwise varied, and many other changes may be made in the form and arrangement of the parts without departing from my invention.

Within the scope of my invention as defined in my broader claims I intend to include constructions in which a substantial part of the supporting-surface is made to conform to the above description, with a fiat bearing-surface, from between which and the glass sheets the air is exhausted, whether the remainder of the table be constructed in this manner or otherv' ise-as, for example, in accordance with the drawings of my prior patent.

I claiml. A glass-holding table having a fiat supporting-surface connected with a vacuum apparatus, .and a sealing means around the flat surface.

2. A glass-holding table having a substantial portion .of its face eonstitutinga iiatsupportizngwsurface and connected with the vacuum apparatus, and a flat covering for said surface. I

Aglasssholdin-g table having the major portion of its face-con stituting a flatsupportin g-surfaee and connected to a vacuum apparatus, and a flat covering for said surface.

4. A glass-holding table having a substan tial portion of its face constituting a flatsup= porting-surface and connected to a vacuumchamber, and a fiuid-chamher in the table and arranged to regulate its heat.

5'. A glass-holding table having a substan-- tial portion of its face constituting a flat supporting-surface and connected to a vacuum apparatus,and a fluid-chamber also connected to this surface.

6. A glass-holding table having .a substantial portion of its face constituting afiatsnpporting-surface and connected to avacuumchamber, .and a flat porous packing arranged to cover this surface.

7, A glass-holding tabl-ehaving a fiat supporting-surface connected to a vacuum apparatus, a flat covering for said surface, and a sealing means around the flat surface.

8. A glass-holding table having a fiat supportingsurface connected to a vacuum apparatus, a flat porous packing arranged to cover the surface, and means for supplyinga fluid to this packing are and the surface to seal the same.

9. A glass-holding table having asubstantial portion of its face constituting a flat supporting-surface and connected to a vacuum apparatus, a fluid-chamber in the table and connected with channels in its face, an-da flat porous packing arranged to cover the flatsurface.

' 1 0. A cell or rib-top :glass-holdin g tableconnected with a vacuum apparatus, and a perforated plate covering the-cell or rib portion.

11. A glass-holding table having a face pronicating With a vacuum apparatus, a waterchannel surrounding each cell, a fiat perforated plate arranged to cover this face, and 15 a flat porous packing arranged to be laid upon the plate.

In testimony whereof I have hereunto set my hand.

GEORGE A. MARSH.

WVitnesses:

G. I. HOLDSHIP, O; E. MAcKoWN. 

